[Suggestion]: change delimiting modifier for attributes from | to ;

[vhyrro]

When using the new attribute syntax proposed by #38, an issue arises when the attributes are broken into many new lines:

- (
    | attribute_1
    | attribute_2
    | attribute_3
  )
  Hello, world!

The pipes could be incorrectly interpreted as a parser as standard ranged tags. For this reason, changing the character used is derised. Upon lots of consideration on the discord ; seems to be the only valid option that doesn't cause any clashes. Time to look like haskell, I guess :)